The present invention relates to a backlight unit, and more particularly to a display having a backlight unit to uniform the brightness thereof.
It is well-known that the liquid crystal display (LCD) is used in many information apparatus, such as laptop computers, because of light weight, thin profile, and low power consumption. In recent years, a backlight unit built in LCD apparatus has become dominant with improvements in brightness and colorization. The backlight units are roughly classified into the direct-lighting type using a reflecting curtain or the like, and the edge-lighting type using a light guide plate. Generally, the backlight unit is disposed under the LCD panel, which utilizes a light source and a plurality of optical elements (such as optical films) to provide uniform light beams to the LCD panel. The LCD panel controls the transmission of the uniform light beams to realize an image display.
Referring to FIG. 1, a conventional backlight unit 10 for providing irradiation to an LCD panel has a frame 12, a light source accommodated in the frame 12, a diffusing plate on the light source, and a plurality of optical films 14. The diffusing plate and the optical films 14 respectively have a plurality of extending portions 16 extending outward from at least one edge thereof. The frame 12 has a plurality of grooves 18 formed on at least one sidewall, respect to the extending portion of the diffusing plate and the optical films. The diffusing plate and the optical films 14 are fixed on the frame 12 in that order from bottom to top through the plurality of extending portion accommodated in the plurality of grooves of the frame 12. However, the groove 18 can not assure a locating of the optical films especially when the backlight unit 10 is perpendicular or inclined locating. In addition, after a long-time use, the optical films 14 are easily to be deformed for high-temperature of the light sources. Thus, the extending portions 16 of the optical films 14 can not be precisely accommodated in the grooves. Therefore, the imprecise locating of the optical films influences the evenness of the outputting light beams over the whole output surface of the optical films, which directly decreases the display images.
Accordingly, what is needed is a backlight unit and a display device that can overcome the above-described deficiencies.